HP A5500 SI Switch Series User manual

HP A5500 EI & A5500 SI Switch Series
IP Multicast
Configuration Guide
Abstract
This document describes the software features for the HP A Series products and guides you through the
software configuration procedures. These configuration guides also provide configuration examples to
help you apply software features to different network scenarios.
This documentation is intended for network planners, field technical support and servicing engineers,
and network administrators working with the HP A Series products.
Part number: 5998-1712
Software version: Release 2208
Document version: 5W100-20110530

Legal and notice information
© Copyright 2011 Hewlett-Packard Development Company, L.P.
No part of this documentation may be reproduced or transmitted in any form or by any means without
prior written consent of Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without notice.
HEWLETT-PACKARD COMPANY MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS
MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not be liable for errors contained
herein or for incidental or consequential damages in connection with the furnishing, performance, or use
of this material.
The only warranties for HP products and services are set forth in the express warranty statements
accompanying such products and services. Nothing herein should be construed as constituting an
additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

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Contents
Multicast overview ······················································································································································· 1
Introduction to multicast····················································································································································1
Comparison of information transmission techniques····························································································1
Features of multicast·················································································································································3
Common notations in multicast·······························································································································4
Advantages and applications of multicast·············································································································4
Multicast models································································································································································5
Multicast architecture························································································································································5
Multicast addresses··················································································································································6
Multicast protocols ···················································································································································9
Multicast packet forwarding mechanism····················································································································· 11
Multi-instance multicast·················································································································································· 12
Introduction to the multi-instance concept ··········································································································· 12
Multi-instance application in multicast ················································································································ 12
IGMP snooping configuration···································································································································14
IGMP snooping overview·············································································································································· 14
Principle of IGMP snooping ································································································································· 14
Basic concepts in IGMP snooping······················································································································· 15
How IGMP snooping works ································································································································· 16
IGMP snooping proxying ····································································································································· 18
Protocols and standards ······································································································································· 19
IGMP snooping configuration task list························································································································· 19
Configuring basic functions of IGMP snooping·········································································································· 20
Configuration prerequisites ·································································································································· 20
Enabling IGMP snooping ····································································································································· 20
Configuring the version of IGMP snooping········································································································ 21
Configuring static multicast MAC address entries····························································································· 21
Configuring IGMP snooping port functions················································································································· 22
Configuration prerequisites ·································································································································· 22
Configuring aging timers for dynamic ports ······································································································ 23
Configuring static ports ········································································································································ 23
Configuring simulated joining······························································································································ 24
Configuring fast-leave processing ······················································································································· 25
Disabling a port from becoming a dynamic router port ··················································································· 26
Configuring IGMP snooping querier ··························································································································· 26
Configuration prerequisites ·································································································································· 26
Enabling IGMP snooping querier························································································································ 27
Configuring IGMP queries and responses·········································································································· 27
Configuring source IP address of IGMP queries································································································ 28
Configuring IGMP snooping proxying ························································································································ 29
Configuration prerequisites ·································································································································· 29
Enabling IGMP snooping proxying····················································································································· 29
Configuring a source IP address for the IGMP messages sent by the proxy·················································· 29
Configuring an IGMP snooping policy························································································································ 30
Configuration prerequisites ·································································································································· 30
Configuring a multicast group filter····················································································································· 30
Configuring multicast source port filtering·········································································································· 31
Configuring the function of dropping unknown multicast data········································································ 31
Configuring IGMP report suppression ················································································································ 32
Configuring the maximum number of multicast groups that a port can join··················································· 32

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Configuring multicast group replacement··········································································································· 33
Configuring 802.1p precedence for IGMP messages······················································································ 34
Configuring a multicast user control policy ········································································································ 35
Displaying and maintaining IGMP snooping·············································································································· 36
IGMP snooping configuration examples ····················································································································· 36
Group policy and simulated joining configuration example············································································ 36
Static port configuration example ······················································································································· 39
IGMP snooping querier configuration example································································································· 42
IGMP snooping proxying configuration example······························································································ 44
Multicast source and user control policy configuration example····································································· 47
Troubleshooting IGMP snooping configuration ·········································································································· 52
Layer 2 multicast forwarding cannot function ···································································································· 52
Configured multicast group policy fails to take effect ······················································································· 53
Appendix (available only on the A5500 EI)··············································································································· 53
Processing of multicast protocol messages ········································································································· 53
Multicast VLAN configuration ···································································································································55
Multicast VLAN overview ·············································································································································· 55
Multicast VLAN configuration task list ························································································································· 57
Configuring sub-VLAN-based multicast VLAN ············································································································ 57
Configuration prerequisites ·································································································································· 57
Configuring sub-VLAN-based multicast VLAN···································································································· 57
Configuring port-based multicast VLAN ······················································································································ 58
Configuration prerequisites ·································································································································· 58
Configuring user port attributes ··························································································································· 58
Configuring multicast VLAN ports ······················································································································· 59
Displaying and maintaining multicast VLAN ·············································································································· 60
Multicast VLAN configuration examples ····················································································································· 60
Sub-VLAN-based multicast VLAN configuration································································································· 60
Port-based multicast VLAN configuration············································································································ 63
Multicast routing and forwarding configuration (available only on the A5500 EI)··············································67
Multicast routing and forwarding overview ················································································································ 67
Introduction to multicast routing and forwarding······························································································· 67
RPF check mechanism··········································································································································· 67
Multicast static routes············································································································································ 69
Multicast traceroute··············································································································································· 71
Configuration task list···················································································································································· 72
Enabling IP multicast routing········································································································································· 72
Configuring multicast routing and forwarding············································································································ 73
Configuration prerequisites ·································································································································· 73
Configuring multicast static routes······················································································································· 73
Configuring a multicast routing policy················································································································ 74
Configuring a multicast forwarding range ········································································································· 75
Configuring the multicast forwarding table size································································································ 75
Tracing a multicast path ······································································································································· 76
Displaying and maintaining multicast routing and forwarding ················································································ 77
Configuration examples ················································································································································ 78
Changing an RPF route········································································································································· 78
Creating an RPF route··········································································································································· 80
Troubleshooting multicast routing and forwarding····································································································· 82
Multicast static route failure·································································································································· 82
Multicast data fails to reach receivers ················································································································ 83
IGMP configuration (available only on the A5500 EI) ···························································································84
IGMP overview······························································································································································· 84
IGMP versions························································································································································ 84

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Introduction to IGMPv1········································································································································· 84
Enhancements in IGMPv2 ···································································································································· 86
Enhancements in IGMPv3 ···································································································································· 86
IGMP SSM mapping············································································································································· 88
IGMP proxying ······················································································································································ 89
Multi-instance IGMP ·············································································································································· 90
Protocols and standards ······································································································································· 90
IGMP configuration task list·········································································································································· 90
Configuring basic functions of IGMP··························································································································· 91
Configuration prerequisites ·································································································································· 91
Enabling IGMP ······················································································································································ 91
Configuring IGMP versions ·································································································································· 92
Configuring static joining ····································································································································· 93
Configuring a multicast group filter····················································································································· 93
Configuring the maximum number of multicast groups that an interface can join ········································ 94
Adjusting IGMP performance ······································································································································· 94
Configuration prerequisites ·································································································································· 94
Configuring IGMP message options ··················································································································· 95
Configuring IGMP query and response parameters ························································································· 96
Configuring IGMP fast-leave processing ············································································································ 98
Configuring IGMP SSM mapping ································································································································ 98
Configuration prerequisites ·································································································································· 98
Enabling SSM mapping········································································································································ 99
Configuring SSM mappings································································································································· 99
Configuring IGMP proxying ········································································································································· 99
Configuration prerequisites ·································································································································· 99
Enabling IGMP proxying····································································································································100
Configuring multicast forwarding on a downstream interface·······································································100
Displaying and maintaining IGMP·····························································································································101
IGMP configuration examples ····································································································································102
Basic IGMP functions configuration example···································································································102
SSM mapping configuration example ··············································································································104
IGMP proxying configuration example·············································································································107
Troubleshooting IGMP·················································································································································109
No membership information on the receiver-side router·················································································109
Inconsistent memberships on routers on the same subnet···············································································110
PIM configuration (available only on the A5500 EI) ··························································································· 111
PIM overview································································································································································111
PIM-DM overview ················································································································································111
PIM-SM overview·················································································································································114
BIDIR-PIM overview ·············································································································································120
Administrative scoping overview·······················································································································123
PIM-SSM overview ··············································································································································125
Relationships among PIM protocols ··················································································································126
Multi-instance PIM ···············································································································································127
Protocols and standards ·····································································································································127
Configuring PIM-DM····················································································································································128
PIM-DM configuration task list ···························································································································128
Configuration prerequisites ································································································································128
Enabling PIM-DM ················································································································································128
Enabling state-refresh capability························································································································129
Configuring state-refresh parameters ················································································································130
Configuring PIM-DM graft retry period·············································································································130
Configuring PIM-SM ····················································································································································131
PIM-SM configuration task list····························································································································131

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Configuration prerequisites ································································································································131
Enabling PIM-SM·················································································································································132
Configuring an RP ···············································································································································133
Configuring a BSR···············································································································································135
Configuring administrative scoping ··················································································································139
Configuring multicast source registration ·········································································································141
Disabling SPT switchover····································································································································142
Configuring BIDIR-PIM ·················································································································································143
BIDIR-PIM configuration task list·························································································································143
Configuration prerequisites ································································································································143
Enabling PIM-SM·················································································································································144
Enabling BIDIR-PIM··············································································································································145
Configuring an RP ···············································································································································145
Configuring a BSR···············································································································································147
Configuring administrative scoping ··················································································································151
Configuring PIM-SSM ··················································································································································153
PIM-SSM configuration task list··························································································································153
Configuration prerequisites ································································································································153
Enabling PIM-SM·················································································································································154
Configuring the SSM group range····················································································································155
Configuring PIM common features·····························································································································155
PIM common feature configuration task list······································································································155
Configuration prerequisites ································································································································156
Configuring a multicast data filter ·····················································································································156
Configuring a hello message filter ····················································································································157
Configuring PIM hello options ···························································································································157
Configuring the prune delay ······························································································································159
Configuring PIM common timers ·······················································································································159
Configuring join/prune message sizes·············································································································161
Displaying and maintaining PIM································································································································161
PIM configuration examples ·······································································································································162
PIM-DM configuration example ·························································································································162
PIM-SM non-scoped zone configuration example ···························································································166
PIM-SM admin-scope zone configuration example ·························································································171
BIDIR-PIM configuration example ······················································································································177
PIM-SSM configuration example ·······················································································································182
Troubleshooting PIM configuration ····························································································································185
Failure of building a multicast distribution tree correctly ················································································185
Multicast data abnormally terminated on an intermediate router··································································186
RPs unable to join SPT in PIM-SM······················································································································187
RPT establishment failure or source registration failure in PIM-SM ································································187
MSDP configuration (available only on the A5500 EI)························································································ 189
Introduction to MSDP···················································································································································189
How MSDP works ···············································································································································189
Multi-instance MSDP ···········································································································································194
Protocols and standards ·····································································································································195
MSDP configuration task list ·······································································································································195
Configuring basic functions of MSDP ························································································································195
Configuration prerequisites ································································································································195
Enabling MSDP····················································································································································196
Creating an MSDP peer connection··················································································································196
Configuring a static RPF peer ····························································································································197
Configuring an MSDP peer connection·····················································································································197
Configuration prerequisites ································································································································197
Configuring MSDP peer description ·················································································································197

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Configuring an MSDP mesh group ···················································································································198
Configuring MSDP peer connection control·····································································································198
Configuring SA messages related parameters ·········································································································199
Configuration prerequisites ································································································································199
Configuring SA message content ······················································································································199
Configuring SA request messages·····················································································································200
Configuring SA message filtering rules·············································································································200
Configuring the SA cache mechanism··············································································································201
Displaying and maintaining MSDP····························································································································202
MSDP configuration examples ···································································································································202
Inter-AS multicast configuration leveraging BGP routes ··················································································202
Inter-AS multicast configuration leveraging static RPF peers ··········································································208
Anycast RP configuration····································································································································211
SA message filtering configuration ···················································································································215
Troubleshooting MSDP ················································································································································218
MSDP peers stay in down state ·························································································································218
No SA entries in the switch’s SA cache············································································································219
Inter-RP communication faults in Anycast RP application ················································································219
MBGP configuration (available only on the A5500 EI)······················································································· 220
MBGP overview ···························································································································································220
Protocols and standards ··············································································································································220
MBGP configuration task list·······································································································································220
Configuring MBGP basic functions····························································································································221
Configuration prerequisites ································································································································221
Configuration procedure ····································································································································221
Controlling route advertisement and reception·········································································································222
Configuration prerequisites ································································································································222
Configuring MBGP route redistribution·············································································································222
Configure default route redistribution into MBGP····························································································222
Configuring MBGP route summarization··········································································································223
Advertising a default route to an IPv4 MBGP peer or peer group ································································224
Configuring outbound MBGP route filtering·····································································································224
Configuring inbound MBGP route filtering·······································································································225
Configuring MBGP route dampening ···············································································································226
Configuring MBGP route attributes ····························································································································226
Configuration prerequisites ································································································································226
Configuring MBGP route preferences···············································································································226
Configuring the default local preference ··········································································································227
Configuring the MED attribute···························································································································227
Configuring the Next Hop attribute···················································································································228
Configuring the AS-PATH attribute ····················································································································228
Tuning and optimizing MBGP networks····················································································································229
Configuration prerequisites ································································································································229
Configuring MBGP soft reset······························································································································229
Enabling the MBGP ORF capability··················································································································230
Configuring the maximum number of MBGP routes for load balancing·······················································231
Configuring a large scale MBGP network ················································································································232
Configuration prerequisites ································································································································232
Configuring IPv4 MBGP peer groups ···············································································································232
Configuring MBGP community ··························································································································232
Configuring an MBGP route reflector ···············································································································233
Displaying and maintaining MBGP ···························································································································234
Displaying MBGP················································································································································234
Resetting MBGP connections······························································································································235
Clearing MBGP information·······························································································································235

viii
MBGP configuration example ····································································································································236
MLD snooping configuration·································································································································· 240
MLD snooping overview··············································································································································240
Introduction to MLD snooping····························································································································240
Basic concepts in MLD snooping·······················································································································241
How MLD snooping works ·································································································································242
MLD snooping proxying ·····································································································································244
Protocols and standards ·····································································································································245
MLD snooping configuration task list ·························································································································245
Configuring basic functions of MLD snooping··········································································································246
Configuration prerequisites ································································································································246
Enabling MLD snooping ·····································································································································246
Configuring the version of MLD snooping········································································································247
Configuring IPv6 static multicast MAC address entries···················································································247
Configuring MLD snooping port functions·················································································································248
Configuration prerequisites ································································································································248
Configuring aging timers for dynamic ports ····································································································248
Configuring static ports ······································································································································249
Configuring simulated joining····························································································································250
Configuring fast-leave processing ·····················································································································250
Disabling a port from becoming a dynamic router port ·················································································251
Configuring MLD snooping querier ···························································································································252
Configuration prerequisites ································································································································252
Enabling MLD snooping querier ························································································································252
Configuring MLD queries and responses··········································································································253
Configuring source IPv6 addresses of MLD queries························································································254
Configuring MLD snooping proxying ························································································································254
Configuration prerequisites ································································································································254
Enabling MLD snooping proxying·····················································································································254
Configuring a source IPv6 address for the MLD messages sent by the proxy··············································255
Configuring an MLD snooping policy························································································································255
Configuration prerequisites ································································································································255
Configuring an IPv6 multicast group filter ········································································································255
Configuring IPv6 multicast source port filtering ·······························································································256
Configuring the function of dropping unknown IPv6 multicast data······························································257
Configuring MLD report suppression ················································································································257
Configuring the maximum number of multicast groups that a port can join·················································258
Configuring IPv6 multicast group replacement ································································································258
Configuring 802.1p precedence for MLD messages······················································································259
Configuring an IPv6 multicast user control policy····························································································260
Displaying and maintaining MLD snooping··············································································································261
MLD snooping configuration examples ·····················································································································262
IPv6 group policy and simulated joining configuration example ··································································262
Static port configuration example ·····················································································································264
MLD snooping querier configuration example·································································································268
MLD snooping proxying configuration example······························································································269
IPv6 multicast source and user control policy configuration example···························································272
Troubleshooting MLD snooping··································································································································277
Layer 2 multicast forwarding cannot function ··································································································277
Configured IPv6 multicast group policy fails to take effect·············································································278
Appendix (available only on the A5500 EI)·············································································································278
Processing of IPv6 multicast protocol messages·······························································································278
IPv6 multicast VLAN configuration························································································································· 280
IPv6 multicast VLAN overview ····································································································································280
IPv6 multicast VLAN configuration task list ···············································································································282

ix
Configuring IPv6 sub-VLAN-based IPv6 multicast VLAN ·························································································282
Configuration prerequisites ································································································································282
Configuring sub-VLAN-based IPv6 multicast VLAN ·························································································282
Configuring port-based IPv6 multicast VLAN············································································································283
Configuration prerequisites ································································································································283
Configuring user port attributes ·························································································································283
Configuring IPv6 multicast VLAN ports·············································································································284
Displaying and maintaining IPv6 multicast VLAN ····································································································285
IPv6 multicast VLAN configuration examples············································································································285
Sub-VLAN-based multicast VLAN configuration example···············································································285
Port-based multicast VLAN configuration example··························································································288
IPv6 multicast routing and forwarding configuration (available only on the A5500 EI)··································· 292
IPv6 multicast routing and forwarding overview ······································································································292
RPF check mechanism·········································································································································292
Configuration task list··················································································································································294
Enabling IPv6 multicast routing ··································································································································295
Configuring IPv6 multicast routing and forwarding ·································································································295
Configuration prerequisites ································································································································295
Configuring an IPv6 multicast routing policy ···································································································295
Configuring an IPv6 multicast forwarding range·····························································································296
Configuring the IPv6 multicast forwarding table size······················································································296
Displaying and maintaining IPv6 multicast routing and forwarding ······································································297
Troubleshooting IPv6 multicast policy configuration ································································································298
Abnormal termination of IPv6 multicast data ···································································································298
MLD configuration (available only on the A5500 EI) ·························································································· 300
MLD overview·······························································································································································300
MLD versions························································································································································300
How MLDv1 works··············································································································································300
How MLDv2 works··············································································································································302
MLD Messages ····················································································································································303
MLD SSM mapping·············································································································································306
MLD proxying ······················································································································································307
Protocols and standards ·····································································································································307
MLD configuration task list··········································································································································308
Configuring basic functions of MLD···························································································································308
Configuration prerequisites ································································································································308
Enabling MLD ······················································································································································309
Configuring the MLD version ·····························································································································309
Configuring static joining ···································································································································310
Configuring an ipv6 multicast group filter········································································································310
Configuring the maximum number of IPv6 multicast groups that an interface can join ······························311
Adjusting MLD performance ·······································································································································311
Configuration prerequisites ································································································································311
Configuring MLD message options ···················································································································312
Configuring MLD query and response parameters ·························································································313
Configuring MLD fast leave processing ············································································································315
Configuring MLD SSM mapping ································································································································315
Configuration prerequisites ································································································································315
Enabling MLD SSM mapping·····························································································································315
Configuring MLD SSM mappings······················································································································316
Configuring MLD proxying ·········································································································································316
Configuration prerequisites ································································································································316
Enabling MLD proxying······································································································································316
Configuring IPv6 multicast forwarding on a downstream interface ······························································317
Displaying and maintaining MLD configuration·······································································································318

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MLD configuration examples ······································································································································319
Basic MLD functions configuration example·····································································································319
MLD SSM mapping configuration example ·····································································································321
MLD proxying configuration example···············································································································324
Troubleshooting MLD···················································································································································325
No member information on the receiver-side router························································································325
Inconsistent memberships on routers on the same subnet···············································································326
IPv6 PIM configuration (available only on the A5500 EI) ··················································································· 327
IPv6 PIM overview························································································································································327
IPv6 PIM-DM overview········································································································································327
IPv6 PIM-SM overview ········································································································································330
IPv6 BIDIR-PIM overview ·····································································································································336
IPv6 administrative scoping overview···············································································································340
IPv6 PIM-SSM overview ······································································································································342
Relationships among IPv6 PIM protocols··········································································································344
Protocols and standards ·····································································································································344
Configuring IPv6 PIM-DM············································································································································345
IPv6 PIM-DM configuration task list···················································································································345
Configuration prerequisites ································································································································345
Enabling IPv6 PIM-DM ········································································································································345
Enabling state-refresh capability························································································································346
Configuring state refresh parameters················································································································346
Configuring IPv6 PIM-DM graft retry period ····································································································347
Configuring IPv6 PIM-SM ············································································································································347
IPv6 PIM-SM configuration task list ···················································································································347
Configuration prerequisites ································································································································348
Enabling IPv6 PIM-SM·········································································································································348
Configuring an RP ···············································································································································349
Configuring a BSR···············································································································································351
Configuring IPv6 administrative scoping··········································································································355
Configuring IPv6 multicast source registration·································································································356
Disabling SPT switchover····································································································································357
Configuring IPv6 BIDIR-PIM·········································································································································358
IPv6 BIDIR-PIM configuration task list ················································································································358
Configuration prerequisites ································································································································358
Enabling IPv6 PIM-SM·········································································································································359
Enabling IPv6 BIDIR-PIM ·····································································································································359
Configuring an RP ···············································································································································359
Configuring a BSR···············································································································································362
Configuring IPv6 administrative scoping··········································································································365
Configuring IPv6 PIM-SSM··········································································································································367
IPv6 PIM-SSM configuration task list ·················································································································367
Configuration prerequisites ································································································································367
Enabling IPv6 PIM-SM·········································································································································367
Configuring the IPv6 SSM group range ···········································································································368
Configuring IPv6 PIM common features ····················································································································368
IPv6 PIM common feature configuration task list ·····························································································369
Configuration prerequisites ································································································································369
Configuring an IPv6 multicast data filter ··········································································································369
Configuring a hello message filter ····················································································································370
Configuring IPv6 PIM hello options···················································································································370
Configuring the prune delay ······························································································································372
Configuring IPv6 PIM common timers···············································································································372
Configuring join/prune message sizes·············································································································374
Displaying and maintaining IPv6 PIM ·······················································································································374

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IPv6 PIM configuration examples·······························································································································375
IPv6 PIM-DM configuration example·················································································································375
IPv6 PIM-SM non-scoped zone configuration example···················································································379
IPv6 PIM-SM admin-scope zone configuration example·················································································384
IPv6 BIDIR-PIM configuration example ··············································································································396
IPv6 PIM-SSM configuration example ···············································································································400
Troubleshooting IPv6 PIM configuration····················································································································403
Failure to build a multicast distribution tree correctly······················································································403
IPv6 multicast data abnormally terminated on an intermediate router··························································404
RPs unable to join SPT in IPv6 PIM-SM ·············································································································404
RPT establishment failure or source registration failure in IPv6 PIM-SM························································405
IPv6 MBGP configuration (available only on the A5500 EI)··············································································· 406
IPv6 MBGP overview ···················································································································································406
IPv6 MBGP configuration task list ······························································································································406
Configuring IPv6 MBGP basic functions····················································································································407
Configuration prerequisites ································································································································407
Configuring an IPv6 MBGP peer·······················································································································407
Configuring a preferred value for routes from a peer/peer group ·······························································408
Controlling route distribution and reception ·············································································································408
Configuration prerequisites ································································································································408
Injecting a local IPv6 MBGP route·····················································································································408
Configuring IPv6 MBGP route redistribution ····································································································409
Configuring IPv6 MBGP route summarization ·································································································409
Advertising a default route to a peer or peer group ·······················································································409
Configuring outbound IPv6 MBGP route filtering ····························································································410
Configuring inbound IPv6 MBGP route filtering ······························································································411
Configuring IPv6 MBGP route dampening·······································································································411
Configuring IPv6 MBGP route attributes····················································································································412
Configuration prerequisites ································································································································412
Configuring IPv6 MBGP route preferences ······································································································412
Configuring the default local preference ··········································································································412
Configuring the MED attribute···························································································································413
Configuring the NEXT_HOP attribute················································································································413
Configuring the AS_PATH attribute···················································································································414
Tuning and optimizing IPv6 MBGP networks············································································································414
Configuration prerequisites ································································································································414
Configuring IPv6 MBGP soft reset ·····················································································································414
Enabling the IPv6 MBGP ORF capability ·········································································································415
Configuring the maximum number of equal-cost routes for load-balancing ·················································417
Configuring a large scale IPv6 MBGP network········································································································417
Configuration prerequisites ································································································································417
Configuring an IPv6 MBGP peer group ···········································································································417
Configuring IPv6 MBGP community··················································································································418
Configuring an IPv6 MBGP route reflector·······································································································418
Displaying and maintaining IPv6 MBGP···················································································································419
Displaying IPv6 MBGP ·······································································································································419
Resetting IPv6 MBGP connections ·····················································································································420
Clearing IPv6 MBGP information ······················································································································421
IPv6 MBGP configuration example ····························································································································421
Support and other resources ·································································································································· 424
Contacting HP ······························································································································································424
Subscription service ············································································································································424
Related information······················································································································································424
Documents····························································································································································424
Websites ······························································································································································424

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Conventions ··································································································································································425
Index ········································································································································································ 427

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Multicast overview
NOTE:
This document focuses on the IP multicast technology and device operations. Unless otherwise stated,
the term
multicast in this document refers to IP multicast.
Introduction to multicast
As a technique that coexists with unicast and broadcast, the multicast technique effectively addresses the
issue of point-to-multipoint data transmission. By enabling high-efficiency point-to-multipoint data
transmission over a network, multicast greatly saves network bandwidth and reduces network load.
By using multicast technology, a network operator can easily provide new value-added services, such as
live webcasting, web TV, distance learning, telemedicine, web radio, realtime video conferencing, and
other bandwidth-critical and time-critical information services.
Comparison of information transmission techniques
Unicast
In unicast transmission, the information source must send a separate copy of information to each host
that needs the information.
Figure 1 Unicast transmission
Source
Receiver
Receiver
Receiver
Host A
Host B
Host C
Host D
Host E
Packets for Host B
Packets for Host D
Packets for Host E
IP network
In Figure 1, assume that Host B, Host D and Host E need the information. A separate transmission
channel must be established from the information source to each of these hosts.

2
In unicast transmission, the traffic transmitted over the network is proportional to the number of hosts that
need the information. If a large number of hosts need the information, the information source must send
a copy of the same information to each of these hosts. Sending many copies can place a tremendous
pressure on the information source and the network bandwidth.
Unicast is not suitable for batch transmission of information.
Broadcast
In broadcast transmission, the information source sends information to all hosts on the subnet, even if
some hosts do not need the information.
Figure 2 Broadcast transmission
In Figure 2, assume that only Host B, Host D, and Host E need the information. If the information is
broadcast to the subnet, Host A and Host C also receive it. In addition to information security issues,
broadcasting to hosts that do not need the information causes traffic flooding on the same subnet.
Broadcast is disadvantageous in transmitting data to specific hosts. Moreover, broadcast transmission is
a significant waste of network resources.
Multicast
Unicast and broadcast techniques cannot provide point-to-multipoint data transmissions with the
minimum network consumption.
Multicast transmission can solve this problem. When some hosts on the network need multicast
information, the information sender, or multicast source, sends only one copy of the information.
Multicast distribution trees are built through multicast routing protocols, and the information is replicated
only on nodes where the trees branch.

3
Figure 3 Multicast transmission
The multicast source sends only one copy of the information to a multicast group. In Figure 3, Host B,
Host D, and Host E, which are receivers of the information, must join the multicast group. The routers on
the network duplicate and forward the information based on the distribution of the group members.
Finally, the information is correctly delivered to Host B, Host D, and Host E.
To summarize, multicast has the following advantages:
•Advantages over unicast: Because multicast traffic flows to the farthest-possible node from the
source before it is replicated and distributed, an increase in the number of hosts does not increase
the load of the source or remarkably add to the usage of network resources.
•Advantages over broadcast: Because multicast data is sent only to the receivers that need it,
multicast uses network bandwidth reasonably and enhances network security. In addition, data
broadcast is confined to the same subnet, but multicast is not.
Features of multicast
Multicast transmission has the following features:
•A multicast group is a multicast receiver set identified by an IP multicast address. Hosts join a
multicast group to become members of the multicast group before they can receive the multicast
data addressed to that multicast group. Typically, a multicast source does not need to join a
multicast group.
•An information sender is called a “multicast source.” A multicast source can send data to multiple
multicast groups at the same time, and multiple multicast sources can send data to the same
multicast group at the same time.
•All hosts that have joined a multicast group become members of the multicast group. The group
memberships are dynamic. Hosts can join or leave multicast groups at any time. Multicast groups
are not subject to geographic restrictions.
•Routers or Layer 3 switches that support Layer 3 multicast are called “multicast routers” or “Layer 3
multicast devices.” In addition to providing the multicast routing function, a multicast router can

4
manage multicast group memberships on stub subnets with attached group members. A multicast
router itself can be a multicast group member.
For a better understanding of the multicast concept, you can compare multicast transmission to the
transmission of TV programs.
Table 1 An analogy between TV transmission and multicast transmission
TV transmission Multicast transmission
A TV station transmits a TV program through a
channel.
A multicast source sends multicast data to a multicast
group.
A user tunes the TV set to the channel. A receiver joins the multicast group.
The user starts to watch the TV program
transmitted by the TV station via the channel.
The receiver starts to receive the multicast data that the
source is sending to the multicast group.
The user turns off the TV set or tunes to another
channel.
The receiver leaves the multicast group or joins another
group.
Common notations in multicast
The following notations are commonly used in multicast transmission:
•(*, G)—Indicates a rendezvous point tree (RPT), or a multicast packet that any multicast source
sends to multicast group G. Here, the asterisk represents any multicast source, and “G” represents
a specific multicast group.
•(S, G)—Indicates a shortest path tree (SPT), or a multicast packet that multicast source S sends to
multicast group G. Here, “S” represents a specific multicast source, and “G” represents a specific
multicast group.
NOTE:
For more information about the concepts RPT and SPT, see the chapters “PIM configuration”
and “IPv6
PIM configuration.”
Advantages and applications of multicast
Advantages of multicast
The multicast technique has the following advantages:
•Enhanced efficiency—Reduces the processor load of information source servers and network
devices.
•Optimal performance—Reduces redundant traffic.
•Distributed application—Enables point-to-multipoint applications at the price of minimum network
resources.
Applications of multicast
The multicast technique has the following applications:
•Multimedia and streaming applications, such as web TV, web radio, and realtime video/audio
conferencing

5
•Communication for training and cooperative operations, such as distance learning and
telemedicine
•Data warehouse and financial applications, such as stock quotes
•Any other point-to-multipoint applications for data distribution
Multicast models
Based on how the receivers treat the multicast sources, the multicast models include any-source multicast
(ASM), source-filtered multicast (SFM), and source-specific multicast (SSM).
ASM model
In the ASM model, any sender can send information to a multicast group as a multicast source, and
numbers of receivers can join a multicast group (identified by a group address) and can obtain multicast
information addressed to that multicast group. In this model, receivers do not determine the positions of
the multicast sources in advance. However, they can join or leave the multicast group at any time.
SFM model
The SFM model is derived from the ASM model. To a sender, the two models appear to have the same
multicast membership architecture.
The SFM model functionally extends the ASM model. The upper-layer software checks the source address
of received multicast packets and permits or denies multicast traffic from specific sources. Therefore,
receivers can receive the multicast data from only part of the multicast sources. To a receiver, not all
multicast sources are valid: they are filtered.
SSM model
Users might be interested in the multicast data from only certain multicast sources. The SSM model
provides a transmission service that enables users to specify the multicast sources that they are interested
in at the client side.
The main difference between the SSM model and the ASM model is that in the SSM model, receivers
have already determined the locations of the multicast sources by some other means. In addition, the
SSM model uses a multicast address range that is different from that of the ASM/SFM model, and
dedicated multicast forwarding paths are established between receivers and the specified multicast
sources.
Multicast architecture
IP multicast addresses the following questions:
•Where should the multicast source transmit information to? (multicast addressing)
•What receivers exist on the network? (host registration)
•Where is the multicast source that will provide data to the receivers? (multicast source discovery)
•How should information be transmitted to the receivers? (multicast routing)
IP multicast is an end-to-end service. The multicast architecture involves the following parts:
1. Addressing mechanism—A multicast source sends information to a group of receivers through a
multicast address.
2. Host registration—Receiver hosts can join and leave multicast groups dynamically. This mechanism
is the basis for management of group memberships.

6
3. Multicast routing—A multicast distribution tree—a forwarding path tree for multicast data on the
network—is constructed for delivering multicast data from a multicast source to receivers.
4. Multicast applications—A software system that supports multicast applications, such as video
conferencing, must be installed on multicast sources and receiver hosts. The TCP/IP stack must
support reception and transmission of multicast data.
Multicast addresses
Network-layer multicast addresses—namely, multicast IP addresses—enable communication between
multicast sources and multicast group members. In addition, a technique must be available to map
multicast IP addresses to link-layer multicast MAC addresses.
IP multicast addresses
1. IPv4 multicast addresses
Internet Assigned Numbers Authority (IANA) assigned the Class D address space—224.0.0.0 to
239.255.255.255—for IPv4 multicast.
Table 2 Class D IP address blocks and description
Address block Description
224.0.0.0 to 224.0.0.255
Reserved permanent group addresses. The IP address 224.0.0.0
is reserved. Other IP addresses can be used by routing protocols
and for topology searching, protocol maintenance, and so on.
Table 3 lists common permanent group addresses. A packet
destined for an address in this block will not be forwarded
beyond the local subnet regardless of the Time to Live (TTL) value
in the IP header.
224.0.1.0 to 238.255.255.255
Globally scoped group addresses. This block includes the
following types of designated group addresses:
•232.0.0.0/8—SSM group addresses
•233.0.0.0/8—Glop group addresses
239.0.0.0 to 239.255.255.255
Administratively scoped multicast addresses. These addresses are
considered locally unique rather than globally unique, and can
be reused in domains administered by different organizations
without causing conflicts. For more information, see RFC 2365.
NOTE:
The membership of a group is dynamic. Hosts can join or leave multicast groups at any time.
“Glop” is a mechanism for assigning multicast addresses between different autonomous systems
(ASs). By filling an AS number into the middle two bytes of 233.0.0.0, you get 255 multicast
addresses for that AS. For more information, see RFC 2770.
Table 3 Some reserved multicast addresses
Address Description
224.0.0.1 All systems on this subnet, including hosts and routers
224.0.0.2 All multicast routers on this subnet
224.0.0.3 Unassigned

7
Address Description
224.0.0.4 Distance Vector Multicast Routing Protocol (DVMRP) routers
224.0.0.5 Open Shortest Path First (OSPF) routers
224.0.0.6 OSPF designated routers and backup designated routers
224.0.0.7 Shared Tree (ST) routers
224.0.0.8 ST hosts
224.0.0.9 Routing Information Protocol version 2 (RIPv2) routers
224.0.0.11 Mobile agents
224.0.0.12 Dynamic Host Configuration Protocol (DHCP) server/relay agent
224.0.0.13 All Protocol Independent Multicast (PIM) routers
224.0.0.14 Resource Reservation Protocol (RSVP) encapsulation
224.0.0.15 All Core-Based Tree (CBT) routers
224.0.0.16 Designated Subnetwork Bandwidth Management (SBM)
224.0.0.17 All SBMs
224.0.0.18 Virtual Router Redundancy Protocol (VRRP)
2. IPv6 multicast addresses
Figure 4 IPv6 multicast format
The following describes the fields of an IPv6 multicast address:
•0xFF—The most significant eight bits are 11111111, which indicates that this address is an IPv6
multicast address.
•Flags—The Flags field contains four bits.
Figure 5 Format of the Flags field
Table 4 Description on the bits of the Flags field
Bit Descri
p
tion
0 Reserved, set to 0
R
•When set to 0, it indicates that this address is an IPv6 multicast address without an
embedded RP address.
•When set to 1, it indicates that this address is an IPv6 multicast address with an
embedded RP address—the P and T bits must also be set to 1.

8
Bit Descri
p
tion
P
•When set to 0, it indicates that this address is an IPv6 multicast address not based on
a unicast prefix.
•When set to 1, it indicates that this address is an IPv6 multicast address based on a
unicast prefix—the T bit must also be set to 1.
T
•When set to 0, it indicates that this address is an IPv6 multicast address permanently-
assigned by IANA.
•When set to 1, it indicates that this address is a transient, or dynamically assigned
IPv6 multicast address.
•Scope—The Scope field contains four bits, which indicate the scope of the IPv6 internetwork for
which the multicast traffic is intended.
Table 5 Values of the Scope field
Value Meanin
g
0, F Reserved
1 Interface-local scope
2 Link-local scope
3 Subnet-local scope
4 Admin-local scope
5 Site-local scope
6, 7, 9 through D Unassigned
8 Organization-local scope
E Global scope
•Group ID—The Group ID field contains 112 bits. It uniquely identifies an IPv6 multicast group in the
scope that the Scope field defines.
Ethernet multicast MAC addresses
When a unicast IP packet is transmitted over Ethernet, the destination MAC address is the MAC address
of the receiver. When a multicast packet is transmitted over Ethernet, the destination address is a
multicast MAC address because the packet is directed to a group formed by a number of receivers,
rather than to one specific receiver.
1. IPv4 multicast MAC addresses
As defined by IANA, the most-significant 24 bits of an IPv4 multicast MAC address are 0x01005E. Bit
25 is 0, and the least-significant 23 bits are the least-significant 23 bits of a multicast IPv4 address.